1. Field of the Invention
The present invention relates to a power source apparatus that can output a voltage of positive polarity and a voltage of negative polarity.
2. Description of the Related Art
Conventionally, as a power source that can output both a voltage of positive polarity (hereinafter, referred to as positive voltage) and a voltage of negative polarity (hereinafter, referred to as negative voltage) from an output terminal, there has been known a power source configured by connecting power sources for respectively outputting positive and negative voltages in series. In this power source, amplifiers are individually provided to control the positive and negative voltages, respectively. The amplifiers amplify differences between target values and voltages obtained by feeding back output voltages to respectively control the positive and negative voltages (refer to the configuration discussed in Japanese Patent No. 03323579). Concerning a power source configured to include a simplified circuit of such a power source capable of outputting positive and negative voltages, Japanese Patent Application Laid-Open No. 2011-130624 discusses a configuration for outputting positive and negative voltages by a simple circuit that uses a capacitive element and two constant voltage diodes on a secondary side of a transformer.
The configuration discussed in Japanese Patent Application Laid-Open No. 2011-130624 includes a circuit configuration more simplified than that discussed in Japanese Patent No. 03323579 but not designed to feed back and adjust the respective positive and negative voltages. Consequently, there is a limitation on the control of the positive and negative voltages with higher accuracy.